Variable shape rotors are known from the prior art, as an example of which was provided by Werner in (U.S. Pat. No. 716,970). Another type of engine was disclosed by Wankel, who established a rotary engine with a fixed shape rotor and epitrochoidal shape stator.
In present invention, during the rotation cycle, the rotor pivoting blades or pistons align alternatively in a lozenge and a square configuration so that the volume between the blades itself, side walls and the stator (contour wall) changes, and in so doing, allows to create a cycling machine.
Rotary engines and cycling machines based on the principle set forth in Edward H. Werner's invention of 1902 (U.S. Pat. No. 716,970) and further inventions developed in greater detail.
German Patent No. 1,295,569, provided a rotary internal combustion engine, in which two pistons are provided, which are connected to the shaft by means of two diametrically opposite arms fixedly connected to the shaft.
A contemporary embodiment of the cycling machine utilizing Werner's principle is described in U.S. Pat. No. 6,164,263, in which roller carriages pivotally connected to the ends of the blades create a lateral support for the rotor and simultaneously provide a cam surface for the rotor shape deformation. In this device, an additional variation of the volume between the blades, side covers and a stator, is achievable due to variation in relative positions of the carriages and blades.
Similar configurations are well known from prior art including U.S. patents by Jordan, Ishida and Niemland. These devices however, do not employ rollers at the end of sealing carriages, save for U.S. Pat. No. 3,387,596, by Niemand where rollers are used in combination with a cam surface for deformation of the shape of a four blade parallelogram.
Parallelogram mechanisms for creating reciprocating movement of the pistons are known from U.S. Pat. No. 5,203,295, issued to Alexander. Multiple applications of unique properties of the parallelogram mechanism are also known, for instance from PCT WO 09105990 by Okulov.
These arrangements are useful, however a common disadvantage exists in that the pivoting blades or links arranged in such configurations are extremely difficult to seal at the pivoting ends.
In respect of the sealing difficulties, different sealing techniques and methods have been described in U.S. Pat. Nos. 3,950,017; 3,690,791; 3,918,41; 4,296,936, etc. Several different types of seals are needed to provide adequate sealing of the device similar to U.S. Pat. No. 6,164,263, which greatly complicates the design and compromises reliability. In addition, the complicated shape of the parts and greater surface area of the combustion chamber both determine high thermal losses and lower efficiency for this type of engine. Eliminating roller carriages in order to create a simpler shape for the combustion chamber (or considering its size near zero) results in the devices similar to those described in a U.S. Pat. No. 3,918,415.
The geometry and numerous configurations of the rotor and stator shapes have been detailed in U.S. Pat. Nos. 3,950,117 and 5,288,217 for different types of variable shape rotors. The shape employed in U.S. Pat. No. 6,164,263 is generally described in the prior art and includes a non deformable rotor having one to four pivoted carriages running in a stator of square or other polygon like shape with rounded corners.
Another variant of a reciprocating cycling machine by Huttlin (as an example see U.S. Pat. No. 6,009,847) employs four two arm levers with the ends of the arms rolling or meshing with each other through gear coupling. The assembly of levers rotates in a circular housing. The disadvantage of the configuration is that the combustion chamber has a very high surface to volume ratio, which leads to thermal inefficiency. Also, the unbalanced lateral forces applied against the cylindrical stator create friction losses and excessive wear of apex seals (FIG. 10) followed by widening of the tolerance gap between levers. This compromises the performance of the already complicated sealing system, reduces the torque and increases complexity of the design.
All these engines have an advantage of being near vibration free contrary to the Wankel and other type of engines with fixed shape rotor or unbalanced pistons. Disadvantages of such engines however exist in that seals at the pivoting ends of the blades or arm levers are complicated. There are still high friction losses due to the significant stress produced by gas pressure and complexity of the shape of the seals and joints.
In addition, the rollers of the carriages are exposed to high temperature combustion gases and suffer from deposition of residue products or plaque from the combustion process. This very complicated configuration of the combustion chamber creates excessive heat transfer to its parts due to large surface area predetermined by the geometry of the pistons (blades). Due to the higher surface area of the combustion chamber/s relative to its volume/s, there are more residues from the non burnt film of the fuel. As in most rotary engines, due to centrifugal action of the rotating rotor forcing the lubricator oil to enter the exhaust, a tendency to have higher overall engine emissions still exists.
There are also well known devices (so-called “cat and mouse” or scissors type engines) realized in a variety of configurations and utilizing principle of creating cycling volumes between rotating inside the circular or toroidal housing pistons or blades. The disadvantage of these engines is the need for creating an external mechanism for variation of the relative position of the pistons. These devices include cams, oval gears, rotating links mechanisms (Rice), etc. Other known types of balanced rotary engines are devices employing cylinders and pistons arranged in a circle and having an activating piston movement cam with a rotating shaft.
Other engines are represented by concepts proposed in the prior art and include a pressure energy converter, rotary engine or compressor as in U.S. Pat. Nos. 4,068,985, 3,996,899; a rotary disk engine as in the U.S. Pat. No. 5,404,850; a rotary planetary motion engine as in U.S. Pat. No. 5,399,078; a rotary detonation engine as in the U.S. Pat. No. 4,741,154; a rotary combustion engine as in DE patent 2,448,828, U.S. Pat. Nos. 3,933,131, 4,548,171, 5,036,809; the Wankel type engine as in the U.S. Pat. Nos. 3,228,183, 4,308,002, 5,305,721, and a continuous combustion engine as in the U.S. Pat. No. 3,996,899. Most rotary engines, and particularly the Wankel and those described in the U.S. Pat. Nos. 3,442,257, 3,614,277, 4,144,866, 4,434,757, DE Patent No. 3,027,208 are based on the principle of volume variation between a curve and a moving cord of fixed length as a single sliding piston and have the common disadvantage of being unbalanced.